1.3.9d "There was a security error when trying to login"

[noderaser]

I've been using ZenCart for almost two years now without problems--pretty impressive considering that my understanding of server-side databases and things of a PHP nature is very scant. Anyway, I have just recently started receiving the "There was a security error when trying to login" message in the admin area. The customer end of the site seems unaffected, and I've gotten an order recently (which I received and filled through email only).

The big puzzler, is that I haven't specifically done much with ZenCart over the last couple of days. I will list the two major things that have been done to my site, in hopes that it may shed light on the cause.

1. Restored MySQL databases from backup. I was doing some work on another part of my site, and managed to nuke the database. So, I restored all of the databases from backup.

2. Upgraded PHP from 5.2.12 to 5.2.13. Did this through my hosting company's site manager. In talking with my hosting company's support, this is supposed to have been rolled back to 5.2.12 although it still shows up as 5.2.13 in the site manager.

One major gap in my information, is that I haven't done anything with admin since before these two changes took place. I tried restoring the database to an even earlier backup (no dice), but have restored the more recent version to preserve the order and customer information that I've gotten since then. The one thing I'm not entirely sure about is the PHP version--aside from the site manager, I'm not sure where else I can check the version number. Either way, it's probably good to stay with the newer release and fix ZenCart around it--unless there is a specific reason not to.

I've been a little more adventurous the past few days, trying new things with other site apps--and maybe got a little too much so since I've managed to break ZenCart. Any assistance or advice would be greatly appreciated; the hosting support person I talked to last night didn't seem to know much about ZenCart--and I'm using a newer version than the one they provide (1.3.8).

I should also add that I'm getting a recurring error in my logs, that started around the time of the PHP upgrade. It is as follows:

Zend Optimizer requires Zend Engine API version 2200600519.
The Zend Engine API version 220090626 which is installed, is newer.
Contact Zend Technologies at http://www.zend.com/ for a later version of Zend Optimizer.

[noderaser]

Through some more troubleshooting with my hosting provider, it appears that there was a change in libphp5.so between PHP 5.2.12 and 5.2.13 that causes the error. Turns out they didn't rollback that file last night, because they were not aware of any changes to it--and it's the same size.

The Zend Optimizer message does not seem to be related to the ZenCart error, because it's still there. May have to do some more looking into that because it is a frequent error and makes it harder to find the more serious ones, but that's not a topic for this forum.